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Fused Quartz

Fused Silica or Fused Quartz (SiO2)

Silica is found almost everywhere in nature, and represents almost 1/3 the mass of the earth’s crust. Vitreous Silica is the generic term used to describe all types of silica glass, and manufacturers refer to the material as either Fused Quartz or Fused Silica.

Fused Silica is an entirely synthetic material, and is technically the purest glass. It has the highest temperature characteristics of any glass, and it often begins as pure silicon gas. Because of the way fused silica is made, it has superior ultraviolet performance to natural quartz and is ideal for applications such as UV transmitting optics.

We at VENTURE SCIENTIFIC® take utmost care to ensure highest quality standards, we select quartz raw material after carefully testing the material for the required standards for selected application.

We supply different sizes and grade of quartz tube such as thick wall quartz tubes, large diameter quartz tubes U & C shape quartz tubes, quartz capillary Tube, Two/Four hole thermocouple tube, One end closed (Flat/Dome) shape Quartz Tubes, Quartz Test Tube and other special shaped quartz items according to customer’s design.

We are also engaged in design and development of quartz product for researchers and industries to ensure the quality standards, purity and temperature range are achieved.

OUR CAPABILITIES

Quartz Glassblowing
Quartz Coldworking
Quartz Machining
Complex Custom Fabrications

Fused Quartz Products

Clear Fused Quartz Tubing
Clear Fused Quartz Rod
Discs & Plates
Microscope Slides
Quartz Flasks
Quartz Beakers
Quartz Crucibles
Quartz Dishes
Quartz Test Tubes

Quartz Standard Joints
Quartz Boats
Quartz Trays
Quartz Wools
Quartz Frits
Quartz Ampoule
Quartz Beads
Custom Fused Quartz

Tolerance of quartz tubes:

OD tolerance 0.1 to 3mm (as per tube dimension)

Wall thickness tolerance 0.1 to 1mm (as per tube dimension)

Siding (max) 0.1 to 0.8 (as per tube dimension)

Ellipticity (max) 0.1 to 3mm (as per tube dimension)

Curvature (max) 2% to 5% (as per tube dimension)

Tolerance of quartz rods:

OD tolerance 0.1 to 3mm (as per tube dimension)

Diameter tolerance 0.1 to 1mm (as per rod dimension)

Thermal Properties

Thermal Conductivity	1.37(W/m°K)
Coefficient Of t\Thermal Expansion(0~1000°C)		2560
Normal Operating Temperature	Continuous Usage	~1050°C
	Non Continuous Usage	~1200°C
Strain Point		~1070°C
Annealing Point		~1140°C

Physical Properties

Thermal Conductivity	Units of Measure	Value
Density	gm/cc (lb/ft3)	2.18
Porosity	(%)	0.01
Tensible Strength	106 Pa	48.2
Young’s Modulus	106 Pa	71.5
Hardness	Kg/mm2	580
Thermal Conductivity	W/m°K	1.37

CHEMICAL PROPERTIES OF FUSED QUARTZ / SILICA

Fused quartz (transparent) and fused silica (translucent) are amorphous products resulting from high temperature treatment of naturally occurring quartz crystals or sand (SiO2). Fused quartz has a nominal purity of 99.99%, and fused silica 99.90%. Fused quartz and silica are attacked by phosphoric acid at temperatures in the range of 150 degrees C or higher, and by hydrofluoric acid at all temperatures.

PHYSICAL & THERMAL PROPERTIES OF FUSED QUARTZ / SILICA

Fused quartz and silica have an extremely low coefficient of thermal expansion which imparts a high resistance to thermal shock. Our fused quartz products can be heated to 1050 degrees C, or higher (1100 degrees C), and immersed in cold water without resultant physical damage. Annealing point is 1140 degrees C, strain point is 1070 degrees C, fusion point is between 1700 and 1800 degrees C.

Devitrification of fused quartz does not usually occur at temperatures below 1100 degrees C under normal conditions. High temperatures accelerate devitrification particularly in the presence of surface contaminants such as alkaline solutions, salts and vapors. To prevent deposit of salts, fused quartz should be handled with gloves. Radioactive materials, hydrogen and certain metals also accelerate devitrification.

Devitrification can be identified, as fused quartz cools below 250 degrees C, by a hazy film caused by micro-fine cracks. Devitrification can be forestalled by washing the quartz surface in a 10% solution of hydrofluoric acid for several minutes at room temperature, followed by a series of rinses in distilled or deionized water, followed by rapid drying.

ELECTRICAL PROPERTIES OF FUSED QUARTZ / SILICA

Fused quartz and silica have excellent electrical strength that remains highly stable with temperature variation. Quartz resistivity (10 to 17th power) ohms/cc at 25 degrees C is in the order of (10 to 17th power) ohms/cc at 1000 degrees C.

Purity and Tolerance / ppm

Quartz, though being abundant in Earth’s crust, takes purification before putting into applications.

Purity is a critical indicator for quartz material. The semiconductor industry, in particular, demands high purity quartz because impurities, even in trace amounts, may impact heat-resistance, wear-resistance and other electrical properties of semiconductor components.

To meet requirements of the semiconductor industry, impurities in processed quartz must be kept to ppm level.

Al	Fe	Ca	Mg	Ti	Mn	B	K	Na	Li	Cu	Co	Ni	Oh
16	0.4	0.6	0.4	0.1	0.1	0.8	2.0	2.3	0.5	5.7	<0.02	0.03	≦3

Coefficient of Thermal Expansion	10-6/°C	0.54
Specific Heat	J/Kg.°K	735
Dieletric Strength	Ac-kv/mm (volts/mil)	28
Dieletric Constant	@1MHz	3.80
Index of refraction @ 587.6nm		1.44

Note:- The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. Venture Scientific® shall not be held liable for any damage resulting from handling or from contact with the above product.

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